For those with fruit experience...

[TheHappyHopper]

Long story short...I have made a strawberry blonde beer a half-dozen times now over the past year. It it really good for the first several weeks, but then the strawberry flavor starts to fade to the point where it is unrecognizable.

Here's the long version...
My typical method:
- Allow my base beer to ferment for 2 weeks
- Add strawberries to secondary. I use frozen strawberries in a sanitized nylon straining bag. I don't do anything else to sanitize the strawberries themselves.
- Let the strawberries sit in secondary for a week before bottling. (I now have the ability to keg, so I can force carb if that will help).

The last batch I brewed on 11/7 and bottled on 12/5. I noted on 12/19 that I thought it was the best tasting batch yet and throughout the holiday season my family drank 90% of the batch. Fast forward to end of January, I entered it into 2 different competitions and got an average score of about 16 - all of the judges noted a harsh, astringency, plasticy, band-aidy, phenolic off flavor. I had saved a few bottles to try when the score sheets came back, and sure enough I tasted the same thing. The strawberry aroma was still partly there, but the flavor had morphed into awfulness. (I'm actually quite embarrassed that a judge had to drink this...sorry if you happen to be reading this )

None of my other beers seem to have that problem, it is unique to this recipe.

My first thought was that the yeast somehow keeps eating away at the strawberry flavor over time causing it to fade. But I would think that putting the bottles in the fridge once they are carbonated would cause that to stop...So I thought my next step would be to kill off the yeast before adding strawberries and then force carbonating in the keg.

One of the score sheets mentioned that it was probably an infection - I think that makes the most sense. Perhaps because the frozen strawberries are not perfectly sanitized when I get them. But if that's the case, wouldn't the beer have ended up way overcarbonated? And if so - what should I be doing differently to keep this from happening?

 

[stratslinger]

Could be a couple things going on here...

If you're only waiting 1 week with the fruit in secondary, there could still be sugars in the beer from the fruit. And while getting those bottles (or the keg, for that matter) into the fridge post-haste can prevent the yeast from chewing through more of those sugars (potentially leading to bottle bombs!), remember you're taking those bottles back out of the fridge for the comp, and comps don't always store their entries in the most beer-friendly manner in the days and weeks leading up to the big event. If there was anything in those bottles that refrigeration was holding at bay - whether fermentation of residual sugars or some sort of infection - those bottles that you entered in the comp are likely going to show the worst of it.

That said - if all it was was residual sugars, I don't think you'd get the phenolic stuff that you and the judges were picking up. Typically, frozen fruit is pretty darned sanitary (I've used it a few times myself with no issues, though I admit it's a pretty small sample size), but anything's possible.

 

[theDREWery]

A week on strawberries can leach strange flavors from the seeds. I've used them to make lots of wine, and never go a full week because of ruined batches early on. Tastes almost woody, green herb, grass-like to me, I can see it being described as phenolic.

Pectic enzyme, about 4 days on the fruit, and maybe citric acid to make the flavor pop.

 

[TheHappyHopper]

If there was anything in those bottles that refrigeration was holding at bay - whether fermentation of residual sugars or some sort of infection - those bottles that you entered in the comp are likely going to show the worst of it.

That's definitely a good point - however, the bottles that I kept at home to try once my score sheets came back were kept in the fridge the whole time once carbonated, and they exhibited the same signs. For the frozen fruit batches that you have done, how quickly do you drink them up? I generally notice this happening after 1.5 months or so.

A week on strawberries can leach strange flavors from the seeds. I've used them to make lots of wine, and never go a full week because of ruined batches early on. Tastes almost woody, green herb, grass-like to me, I can see it being described as phenolic.

Pectic enzyme, about 4 days on the fruit, and maybe citric acid to make the flavor pop.

I always kind of wondered about the length of time that I leave the strawberries on for. I was pretty sure that when I first started looking into the style, I saw people who claimed they left it on anywhere from a few days to 2+ weeks, so I figured 1 week was about average. I know that after a week in the beer, the strawberries look pretty gross...I did notice that when I bottled this last batch (ended up sitting 9 days due to being busy), it seemed like it had an odd flavor like you are describing (but that faded with conditioning). I will try cutting it back to 4 days and see if that helps at all.

Has anyone used campden tablets / potassium sorbate to stop fermentation before adding fruit? I'm thinking about trying that before adding the fruit this time around.

 

[theDREWery]

I've used campden and sorbate in wines, but never in beer. Keep in mind it wouldn't carb in the bottle. Another thing to consider is that strawberries are about 91% water and 5% sugar, so you could mash them up in a pan and cook the juices out of the fruid. Strain, simmer, add the concentrated juice, but you would loose some aromatics.

 

[stratslinger]

That's definitely a good point - however, the bottles that I kept at home to try once my score sheets came back were kept in the fridge the whole time once carbonated, and they exhibited the same signs. For the frozen fruit batches that you have done, how quickly do you drink them up? I generally notice this happening after 1.5 months or so.

I've used blueberries almost exclusively - though I've used raspberries once or twice too. The flavor contributions theDREWery is talking about, that are related to strawberries, are something very new to me.

That said, the blueberry and raspberry beers I've made have last (in the keg, keep in mind!) anywhere from 5ish weeks to maybe 3 months... I don't ever recall a significant change - and definitely not the kind of degradation you're seeing.